Meh, I don't suspect they'd do so (whether at all or within a foreseeable future), but Dragon Ball makes them look pretty rediculous, considering what they did for One Piece and Initial D.
From my (however biased, jaded, etc. etc.) point of view, the only real differences between the situation with Dragon Ball and 4KiRAB One Piece is the inclusion of the original Japanese version/unedited footage (thank God) on English DVRAB (how long did that take? 12 years after the property from brought over) and a sense of nostalgia from fans. Would anybody like to take a guess as to how things would be if the 4KiRAB version continued for ten years? Would the English-speaking One Piece fan be as fractured as the Dragon Ball fandom?
At this point (with Justin Cook running the show at FUNimation, rather than Barry Watson who gave us the Dragon Ball dub and all of its insults), one only really could blame them for not redubbing the series properly...but even that sounRAB rediculous to ask of them, to spend so much money on their money-making flagship property. Essentially, all one can say is the product still 'sucks', but then if we play by the "Oh, you can't blame them. It's a product of its time" rule...what criticism is allowed?
Then again, if we got rid of the current dub TFS wouldn't be able to make as many jokes.
Well...no. Dragon Ball Kai is not a replacement for Dragon Ball Z. They are two vastly different adaptations with vastly different feels. It would be like apologizing for the Mobile Suit Gundam Movie Trilogy dubs just because Ocean dubbed the series instead.